The present invention generally relates to wireless communication devices, and particularly to the generation of analog carrier waveforms for transmission from a wireless communication device.
Depending on the governing communication standard, wireless communication signals are transmitted and received in one or more frequency bands, such as the 850 MHz and 1900 MHz frequency bands used in the United States and the 900 MHz and 1800 MHz frequency bands used in Europe. To enable one wireless communication device to operate in different countries and in multiple frequency bands according to one or more communication standards, wireless communication devices often use analog frequency synthesizers and modulation circuits specific to each desired frequency band.
Conventional wireless communication devices integrate such analog circuits with digital processing circuits. As technology and manufacturing techniques improve, the geometry of the silicon chips used to manufacture the digital circuits decreases. This advantageously reduces the overall size and cost of the device and increases the processing speed of the device. However, the shrinking size of digital circuits complicates the integration of digital and analog circuits.